The known structure of a fuel cell includes a membrane electrode assembly where electrodes are arranged on both sides of an electrolyte membrane having proton conductivity. The electrode includes a gas diffusion layer arranged to spread a reactive gas over the entire electrode plane and a catalyst layer arranged to support a catalyst for accelerating the fuel cell reaction (PTL1).
During power generation of the fuel cell, hydrogen and oxygen as the reactive gases may respectively pass through the electrolyte membrane and migrate to the opposite electrodes to the electrodes that originally receive the respective supplies of the reactive gases. In such cases, hydrogen and oxygen may be present simultaneously on the same electrode side of the membrane electrode assembly and may react with each other to produce hydrogen peroxide. The produced hydrogen peroxide may be radicalized to hydrogen peroxide radical, which is known as a cause of degrading the electrolyte membrane.
The gas diffusion layer is often made of a fiber base material having electrical conductivity. Fluffs as small projections are present on the outer surface of the fiber base material or more specifically at the edge of the fiber base material. In the membrane electrode assembly, the fluffs may be stuck into the electrolyte membrane and damage the electrolyte membrane. There has been no sufficient measure proposed to prevent such degradation of the electrolyte membrane.